In the use of machinery for moving or lifting loads, it is desirable to have high operator visibility through and about the structure while using a relatively simple design. For example, a common application of such machinery involves the mast assembly for a forklift truck or other material handler. Mast assemblies often contain one or more fixed uprights attached to a vehicle with a movable upright mounted on the fixed uprights by rollers. A carriage carrying, load-engaging fork is mounted for movement on the movable uprights. The movable uprights and carriage can be selectively elevated to retrieve or place loads as desired.
In such mast assemblies the forward visibility of the operator can be restricted by the uprights and the carriage. Machinery design involving the addition of hydraulic jacks and chains which can control the movement of the uprights and carriage can be critical in that it is undesirable to further restrict the visibility or to add an additional complicated structure or weight to the vehicle.
Marina style forklifts are used for storing relatively small boats on storage racks at several lift heights. These forklifts have vertically-oriented masts that are adapted to move or tilt between a vertical orientation and a second orientation wherein the mast is tilted slightly toward the operator thereby positioning the boat more securely in a forklift. Hydraulic jacks can be attached to the mast portion of the forklifts and used to move the masts between the vertical and second orientations.
These tilt hydraulic jacks are attached to the mast portions of the forklifts by the use of structural cross members. On many marina style forklifts, there is a blind spot when the boats are raised to elevations of a certain height. This blind spot is caused by the structural cross member where the tilt hydraulic jack is attached to the mast, and can hinder an operator's view of critical portions of the boat and the fork as the operator attempts to position the boat or other loads on storage racks.